冷轧对Fe-16Mn-0.6C-2.5Al TWIP钢微观组织及力学性能的影响

Influence of cold rolling on microstructure and mechanical properties of Fe-16Mn-0.6C-2.5Al TWIP steel

利用金相显微镜（OM）、透射电镜（TEM）、扫描电镜（SEM）、X射线衍射仪（XRD）等仪器,研究了冷轧对Fe-16Mn-0. 6C-2. 5Al TWIP钢的微观组织和力学性能的影响。结果表明,随着冷轧变形量的增加,试样的屈服强度和抗拉强度升高,但伸长率降低,在拉伸过程中更难发生孪生。试样的加工硬化率随应变的增加总体呈下降趋势。当施加10%～50%冷变形时,含有退火孪晶的等轴晶粒被拉长,组织发生亚结构的演变,包含位错、孪晶及位错和孪晶的相互作用,依次出现滑移带、一次孪晶、二次孪晶、剪切带及微量ε马氏体。断口分析表明,随着冷轧变形量的增加,试样的断裂脆性增大。

The influences of cold rolling on microstructure and mechanical properties of Fe-16 Mn-0. 6 C-2. 5 Al TWIP steel were studied by metallographic microscope（OM）,transmission electron microscope（TEM）,scanning electron microscope（SEM） and X-ray diffraction（XRD）. The results show that the yield strength and tensile strength of specimens increase with the increasing of cold rolling deformation,whereas the elongation decreases,and the twins are more difficult to produce during stretching. Therefore,the working hardening rate of specimens decreases with the increasing of strain. When 10%-50% cold deformation is applied,the equiaxed grains containing annealed twins are elongated,and the evolution of substructures in the organization happens including dislocations,twins and the interaction of dislocations with twins. Furthermore,the slip bands,the first twins,the secondary twins,the shear bands and a small amount of ε martensite appear in sequence. The fractography shows that with the increaing of cold rolling deformation,the fractures become more and more brittle in the specimens.